Air compressor



Sept. 13, 1932. v J, 0 0 1,876,736

AIR COMPRESSOR Filed Oct. 12, 1929 2 SheetsSheet l F. J. OMO

AIR COMPRESSOR Sept. 13, 1932,.

FiI ed Oct. 12. 1929 2 Sheets-Sheet 2 d Mil .Illllll-ZIE invention will appear from the Patented Sept. 13, 1932 FRANK J. 0M0, or'rortr won'rrr, 'rExAs AIR COMPRESSOR Application filed October 12, 1929. Serial This invention relates to improvements 1n air compressors and more particularly relates to an improved construction of opposed p1ston compressors and apparatus for reclproeating the pistons. v

' One of the objects of this invention 18 to provide an air compressor structure wherein the volume of air compressed at each stroke will be substantially doubled without increasing the weight or size of the compressor.

Another object of this invention 1s to provide an opposed piston air compressor whereby the full energy of the opposed pistonswlll be available for compressing a1r. Another object of this invention 1s to provide an improved construction of opposed piston motor-adaptedas an air compressor whereby greater volumes of a1r may be compressed with the same amount of energy, due to the reduction of the reciproeatlng'losses, and the increased size. of he compression chamber. Another object of this invention is to provide an opposed piston type air compressor having a greater cooling area and having more efiectively driven opposed plstons.

Another objectof this invention is to provide a novel means for transmitting, the rotating energy of a crank shaft toan oppose piston type air compressor whereby theeam mechanism is adapted to occupy a minimum space and which is of a more simplified construction.

Another object of this invention is to pro.

vide a poppet and sleevevalve, opposed piston, air compressor having a simplified piston operating structure which ismore efficient in use, has fewer parts, and inwhich friction losses have been reduced to a minimum. f Further objects and advantages ofv this following description thereof, taken in connection with the attached drawings, which illustrate a preferred form of embodiment of single cylinder air compressor. according to my invention, and in which, j

Fig. 1 is a side el'evationof the air compressor having parts broken away to show the internal eonstructionthereof.

,plicated and such tomof the crank case. '22 reciprocates within'the sleeve 18 and -is .up'per piston head.

7 rollers.

No. 399,114. I

Fig. 2-is a central section of the compresf 1 sor. Fig. 3 is a detail section on the line 3-3 of Fig. 1. j a

-Fig. & is a detail section substantially on line 4-4: of Fig. 2.

Double acting compressors for air and other gases have been used heretofore,but in the prior constructions, either duplicate cylinders operated from a central shaft or a common cylinder having pistonsoperated from separate spaced shafts have been used. The valve mechanism has been extremely compumps have been in more or less disfavor. Those disadvantages are obviatedin the present construction. The. air compressor .10- shown to illustrate my improved forrnjo'f construction comprises a crank case 12 having the lower'removable portion 13 and the cylinder 14 secured thereto; an upper piston head 16 connected to the sleeve 18 and the lower piston head 22 reciprocate within; thecylinder 14 inopposed relation. The sleeve 18 extends substantially the length of the cylinderand the integral arms 18a project into the crank ease to cooperate with the wrist pin 20 near the: hot- The opposed piston driven from the connecting rods 32 by the so driving pin 2% in the skirt of the piston and is rotated to oppose'the compression of the The crank shaft 26 is provided with a cam 28, known as a Gassinian oval having opposed concave sides 28a and substantially circular ends 2812. Cam rollers 31 journaled' on intermediate link pins 30, cooperate with the sides ofthe cam 28 and are joined by links 32 to the wrist pins 20-and 24., A roller 34 is supported on the wrist pin 24 and a similar roller 36 is journaled onvthe wrist pin 20. The rollers 34 and36 cooperate with the sides of the cam 28 in such manner that the rollers are always in contact [at diametricallyopposedj positions on the cam; similarly with the roll- 'ers 31,. which are always in contact with the cam 28 at opposed positions, depending on the number of cylinders and number of-eam The center line of the rollers. 31

. the cooperating side of the cam 28,

is always perpendicular to the rollers 34 and 36 When the crank shaft 26 is rotated from the position shown in Fig. 2, the opposed pistons 16 and 22 will separate as the circular portions 286 of the cam 28 recede from the rollers 34 and 36 and force the rollers 31 further apart. -At a maximum position the circular portions 286 of this cam will then be spaced between the rollers 31.and the resulting compression chamber will be at its maximum volume.

N o valves arerequired, for when the piston head 16 is moved to its maximum outward position, the port 40 in the sleeve 18 will be closed and out of communication with port 42 in the cylinder 14. On this outward stroke'a vacuum being created by the receding movement of the opposed cylinder outward and the opposite cylinder downward, the spring loaded poppet valve 44 will open, permitting the air to pass into the compression chamber 46. No other valve mechanism is required. When the maximum outward stroke is reached and the crank shaft continues to turn, the curved portion'28b of the cam will then recede from the roller 31Vand proceed toward the rollers 34 and 36 respectively. The links 32 maintain the contact of the fourrollers on the cam andwhile the cam is receding from two ofjtlie rollers other portions of the cam are in'contact with the remaining two rollers to reciprocate the pistons. WVhen the head 16 starts its downward movement the vacuum condition in the chamber 46 ceases, the poppet valve- 44 automatically closes and the air is compressed between the upper cylinder head 16 and the lower piston head 22, which are now moving toward each other. Meantime the head 16 having moved downward due to the action of the cams and the sleeve 18,'the port 40 in the sleeve 18 comes into cooperation with the port 42 in the cylinder 14 as clearly shown in Fig. 2, and the compressed air will rush from the cylinder into the manifold 48 to the discharge conduit 50.

As shown. in Fig. 3 the wrist pin 20 passes thru the roller 36 and four'links 32 are provided which project upwardly to the wrist pins 30-pairs of the links being parallel to each other and projecting upward on either Trunnions 52 are secured on the projecting ends of the wrist pin 20 and are guided in guides 54 fixed in the crank case on each side of the central roller 36 so that the roller 36 will move upward and downward in a straight line directly below the pistons.

Means to cool the cylinder is provided by the fins on the outer surface of the cylinder 1 4 which insure sufficient radiation of the heat to permit the compressor to work at normal temperatures. The manifold 48 may also be constructed to radiate heat rap cated valve mechanism, but one 22 and cylinder head 16 in opposed directions, the head and piston periodically separating and coming substantially together, alternately draw in a charge of gas, compress it, and discharge the compressed gas. As the pistons separate the air rushes in past the poppet valve 44, and when the head 16 reaches the outer end of its stroke, the poppet valve will close and the compression begins.

As the rollers are always in contact with the surface of the cam, and as the link mechanism positively positions each of the rollers, it will be obvious that upon rotation of the driving shaft that the opposed pistons will be positively reciprocated. The links maintain a parallelogram shape as the opposite sides are always parallel and a continuous reciprocating motion can be had by the rotation of the cam within the center of the parallelogram. It is of course possible to vary the shape of the cam surface to bring about different rates of movement of the pistons as for example: it may be desirable to provide for rapid motion near the end of the stroke and a relatively slower motion of the pistons as they reach the inner compressed position as the compression at that time requires the greatest force per unit distance of movement. 7

It is also to be noted that by extending the sleeve of upper cylinder head, downward below the crankshaft and projecting the skirt of the piston downward to the crankshaft, it is possible to have a common compression chamber and also have'a common crank or driving shaft to reciprocate both piston and cylinder head simultaneously. This reduces the number of working parts and provides for increased compression.

It is also obvious that with the same volume of compression chamber, it isonly necessary to have one half the stroke as both the cylinder head and piston move. The saving in friction and wear is apparent.

The Cassinian oval cam is also of consider able advantage over the usual crank shaft and pitman arrangement as the stresses on the driving shaft are balanced by the contact of the four rollers at once on the cam. There are no sudden power impulses and the device will run smooth and quiet. This is particularly true due to the absence of complipoppet valve which works automatically and a sleeve Valve being provided. This also saves considerable energy.

With the present construction, the greatest amount of energy is directly converted into compression of the gases and in view of the opposed relation of the pistons, both outward and inward, power losses are reduced to a minimum. This pump is particularly desirable for air compression as it is provided with cooling fins and an open cylinder, and as it has few working parts, it is well adapted for continuous, rugged work.

While Ihave shown a preferred form of embodiment of this invention, I am aware that other modifications may be made, and I therefore desire a broad interpretation of the claims within the scope and spirit of the invention and limited only by the claims appended hereinafter.

I claim:

1. In a air compressor of the class described, a cylinder, opposed pistons adapted to reciprocate in said cylinder, a driving shaft, a cam secured to said shaft, anti-friction rollers carried by each of the pistons and bearing upon the cam at substantially diametrically opposite points and linkage between the rollers to positively hold all of said rollers in contact with said cam.

2. In an air compressor of the opposed piston type having a pair of operative pistons, one of said pistons reciprocating in the other piston, a driving shaft, a driving cam secured to said shaft, an anti-friction member carried by each of the pistons and each anti-friction member bearing upon the cam at substantially diametrically opposite points and means engaging the cam and operatively connected to said anti-friction members to force said members to engage said cam at all times.

3. In an air compressor of the class described, a cylinder, a crank case, opposed pistons operatively reciprocated within said cylinder, shafts carried by the pistons and intersected by the axes of the latter, rollers mounted on the shafts, a power shaft, a cam secured to the power shaft and bearing at substantially diametrically opposite points upon said rollers, and a guide in said crank case, one of said piston shafts reciprocating therein.

4. In an air compressor of the opposed piston type, a pair of pistons, one of said pistons having a skirt forming a compression chamber with the other piston, rollers carried by the pistons, additional rollers linked to said first rollers, a cam having a Gassinian oval shape, the first of said rollers and the second of said rollers bearing at diametrically opposite points upon said cam. said second rollers engaging stantially right angles to said first rollers, and a driving shaft secured to said cam and adapted to reciprocate said pistons.

. said cam and adapted to be said cam at sub-' 5. an air compressor ofthe class described, a cylinder, opposed pistons within said cylinder and means to reciprocate said pistons, said pistons having arm extensions,

a shaft operatively connected to said extensions, a roller mounted onsaid shaft, a drivingshaft extending thru'one of said pistons and between some of the arms of the latterand a cam mounted'on said driving shaft'engaging said roller andmovable arms of the piston.

6. In an air compressor of the class de' scribed a piston having guide trunnions, stationary guideways in operate and an anti-friction member carried by the piston a cam engaging said anti-friction member and a power shaft to which the cam is secured.

7 In an air compressor of the class described, a stationary cylinder, stationary guideways arranged parallel to the axis of said cylinder, a piston cooperating with the cylinder, guide members on the piston engaging said guideways, piston, a cam engaging said roller and a driving shaft upon which the cam ismounted.

8. In an air compressor a stationary cylinder, stationary guideways arranged parallel to the axis of the cylinder, oppositely projecting guide members carried by the piston and slidable in said guideways, an anti-friction member carried by the piston, a cam engaging said anti-friction member at a point substantially in and a driving shaft on which the cam is mounted.

9. In an opposed piston type air compressor, a stationary cylinder, a plurality of pistons cooperating with ing shaft, a cam fast on said shaft, rollers on said pistons, said rollers cooperating with reciprocated by it.

10. In a gas compressor of the opposed piston type, a crank case, a cylinder secured to. said crank case, a reciprocating piston within said cylinder, a sleeve adapted to receive and reciprocate said piston, a driving shaft, said sleeve extending beyond said driving shaft, a

second reciprocating piston mounted within said sleeve and cam means adapted to reciprocate said pistons simultaneously away from and toward each other, and means to introduce a gas and means to remove the compressed gas.

11. In a gas compressor of the class described, a cylinder a plurality of pistons actuated within said cylinder, one of said pistons adapted to be reciprocated within the other piston, driving sleeve extending thruout the length of said cylinder, a cam cooperating with the end of said sleeve and secured to a driving shaft to reciprocate said piston, said piston automatically opening to permit inflow of gas therethrough.

between the other i a rollercarried by the ,bb

line with the axis of the piston i.

the cylinder, a drivone of said pistons having a which said trunnions '80 rocated within said 12. In a gas compressor of'the class described a crank case, a driving shaft mounted in said-crank case, a cylinder secured to said crank case, opposed pistons adapted to recipcylinder, a driving sleeve secured to the upper piston and extending below the driving shaft, anti-friction rollers secured in the skirt of one of said pistons and in the end of the driving sleeve of the other piston, a cam secured to said driving shaft adapted to contact with said rollers at diametrically opposite points and additional means adapted to maintain the rollers in contact with said cam at all times.

13. An opposed piston type gas compressor having an open cylinder in which said opposed pistons are reciprocated, said cylinder being provided with a compressed gas manifold, an automatically opening intake mechanism, cooling fins on the surface of said cylinder and a parallelogram linkage secured to said opposed pistons and adapted to be varied in shape to reciprocate said pistons and to separate said pistons the maximum amount on intake and to simultaneously force said pistons together for compression.

In testimony whereof I have aflixed my signature to this specification.

FRANK J. OMO. 

